1. Field of Invention
The present invention is related to a positioning and securing device for plate-shaped tools intended for the hot-pressure transfer of portions of a metallic film web onto a paper or cardboard substrate.
This device comprises a supporting and heating plate for these tools, covered by a plurality of apertures distributed according to a determined periodicity and adapted to receive securement means for these tools. It is also related to a process for producing a template for positioning these tools on the supporting and heating plate.
2. Brief Description of the Background Art
Relatively thick plates, in which are bored a plurality of evenly distributed apertures and adapted to receive a certain number of tools corresponding to a kind of printing plate positioned and secured to supporting plate, are already in use. Such a plate, thus provided with printing plates, is mounted in a machine fed with blanks of cardboard or paper on the one hand and with a metallic film web on the other hand, for the hot transfer of metallic film portions onto the blanks of cardboard by means of the tools positioned on the supporting plate. Such machines are, for example, used for printing onto packagings. Usually, this printing by means of metallic films follows embossing of the cardboard blanks, so that it is important that the printing plates are positioned accurately so that the printing of the metallic film registers exactly with the imprints made by embossing.
Taking into account the cost of such a supporting and heating plate, it would be too expensive to use to print only one packaging pattern. Furthermore, due to its weight it is not easy to manipulate, which would not facilitate is repositioning. Consequently, one supporting and heating plate is generally used for each machine. When changing the work, it is, thus, necessary to remove the printing plates from the supporting plate and to position other printing plates corresponding to the next job. Since the printing plates are mounted in the cold state but they operate in the hot state, because metals expand when heated, it is not possible to take reference measurements from a preceding printed blank, since the preceding printing resulted from the spacing between hot printing plates. Thus, the positioning operation is exceedingly long and, typically corresponds to a working day. The cost of this operation obviously impacts more heavily on the cost of the printed workpieces in the case of relatively small printing lots.